Aquatic Sciences Meeting, Albuquerque 2001

CS14 Fish and Fisheries: Environmental Quality and Ecology

Date: Thursday, February 15, 2001, Time: 4:45:00 PM

Location: Sandia/Santa Ana

Macy, W, K, University of Rhode Island, Grad. School of Oceanography, Narragansett, USA, wkmacy@gsosun1.gso.uri.edu

FEEDING BEHAVIOR OF ATLANTIC MACKEREL AND HERRING AT LOW LIGHT LEVELS

Atlantic mackerel and herring bite- and filter-feed. Laboratory experiments were conducted with schools of fish fed primarily copepods, Calanus and Metridia, under a range of reduced light levels to determine their feeding rates and to document feeding behaviors. Mackerel filter-fed at all light intensities; herring fed mainly by biting. Mackerel feeding rates (volume swept clear) varied directly with light level and prey concentration, but herring feeding rates were relatively low at all light levels, independent of light level. Feeding swimming speeds (SS) for both species were consistently higher than non-feeding speeds (routine), but herring routine and feeding SS were somewhat higher. In both cases routine and feeding SS decreased with light level. Mackerel formed distinct linear schools, but herring remained dispersed throughout the tank. Thus, mackerel can apparently continue effective feeding throughout the night, while herring apparently cease feeding at sunset. Predation on cod and haddock larvae on Georges Bank by historically high stock levels of mackerel may be, in part, responsible for the slow recovery of these important groundfish stocks.

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Aquatic Sciences Meeting, Albuquerque 2001

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